Production of ground enamels.



' PHILIBP EYER, OE HALBERSTADT, GERMANY, ASSIGNOR TO THE FIRM STATES PATENT onFIoE.

OE RUDOLPH xonrr & 00., or OES'IRICH-ON-THE-RHINE, GEBMANY.

PRODUCTION OF GROUND ENAMELS.

No Drawing.

To all whom z't-may concern:

Be it known that I, PHILIPP EYER, a sub-. ject of the German Emperor, and resident My invention relates to the production of ground-enamels for coating 1ron andother goods. As is well known, certain metal oxids, such as the oxids of cobalt, nickel,

manganese, copper and other metals are added to the ground-enamel inorder to improve its capacity of adhering to/the object 'to be enameled. Of the oxids cited theoxid of cobalt is by far the best, while nickel oxid is cheaper but less eflective.

If the ground-enamel is burnt in the presence of such metal oxids, it assumes an undesirable more or less dark color In general those ground-enamels which in melting assume the darkest color adhere best to the object to be coated. The intensity of color therefore offers to the expert an indication of and guide for determining the quality of the ground-enamel, and in this sense the expert speaks of the coloringof the ground by metal oxids. All experts however have agreed that the cobalt oxid to be added to ground-enamels should be absolutely pure or technically pure.

I have now ascertained that the very expensive pure oxid may be replacedwith ad- .vantage by certain cheap ores containing the oxids of cobalt and nickel oxid compounds or at least forming such oxids during further treatment, the ground-enamel thus obtained being not only cheaper but also offering a higher resistance to all kinds of influences. Preferably such ores should beused as contain a high percentage of cobalt oxid or cobalt and nickel oxids or of the carbonates of said metals. In-practice the ores sold under the name'of Caledonim or New- Qaledonian cobalt ores have given excellent results, such ores containing, besides a high percentage of cobalt and nickel oxide. considerable quantities of oxygen compounds 'Ifsuch f ores are used, the rather black Specification of Letters latent.

oxid, 5.5 cobalt oxid Patented Dec. 11, 1917.

' application filedluly 21, .1915. Serial No. 41,196.

burnt ground shows a greater adhesive power than a ground mixture prepared withcorresponding quantities of pure oxids. It has not been possible to find out why this is so; possibly the physical state of the oxids contained in the ores plays a certain role.

In selecting the'ores care should be taken first of all to have a high percentage of cohalt in the ore. Ores containing sulfur and arsenic are unsuited, and in those cases, where ores free of sulfur and arsenic are not to be had, care should be taken to remove these undesirable constituents. The pres ence of iron oxid in the ore is not generally objectionable although it is not recommended to employ ore having, an especially high iron content.

It is of course not possible to use all ores containing the oxids or carbonates in question, but it is easy to ascertain the qualification of any ore by a simple test. In some cases the ores may be supplemented by pure oxids, a deficiency of the ore with regard to one or the other constituent being thus .counterbalanced by an addition of corresponding quantities of mixing different ores. all this W1ll prove unnecessary as there are pure oxids or by In general however sufficient quantities of ores available which the great deterioration ofthe color caused i by such ores they haveine-ver been used commerclally. As shown in the beginning, the use of cobalt compounds for coloring coverenamels has nothing whatever to do With the reinforcing of ground enamels by an addition of cobalt oxid, the'coloring matter being in case completely burnt.

I claim .1. A ground-enamel batch compos'Ttionineluding anore free from sulfur andarsnic and comprising a mixture of metal compounds containing cobalt oxid, for the pur pose described.

2. A ground enamelbatch composition ineluding an ore free from sulfur and arse nic-and comprising a mixture of metal compounds containing cobalt and nickel, for the purpose described.

a creasethe adhering --capacity of the enamel and ore, free fromsul-fur and arsenic,' containing oxidsiof cobalt, nickel, and manganesef 5. The herein described method of preparing a ground-enamel batch composition which comprises freeing ore containing an oxid 'of metal adapted to increase the adhering capacity of an enamel from sulfur and a senic and thereafter addingvsl lch filgilfig ore to'a suitable enamel mixture; T

6. The herein" described method dP'p're: paring a ground-enamel batch composition which comprises freeing-ore containing 60 20 ball) oxid'from sulfur and arsenic and thereafter adding such treated ore to a suitable enamel mixture.

In testimony whereof I have signed my name to this specification in the presence of Qoplen of this patent may be obtained fosfive cents each, by'eddresslng the "commissioner of Patents, 3 Washington, D. c. i V 

